A London council that launched a cost-cutting drive inspired by no-frills airlines has been served with an injunction to stop it ending live-in wardens for older people in sheltered housing.

Mr Justice Silber, sitting in the high court, has ordered Conservative-controlled Barnet to take no further steps to remove residential wardens from 52 sites across the borough, pending a possible judicial review. The challenge by a group in the sheltered housing could be widened to include 50 other councils where similar cuts are proposed.

Residents in Bradford, Bristol, Scarborough, Exeter and Evesham have signed up to be part of further high court actions as local authorities face a crisis in public finances which could wipe £26bn off council budgets by 2013, according to the Institute of Fiscal Studies.

The order against Barnet is a setback to the reforms proposed by the council leader, Mike Freer, seen as a test of wider Conservative policy should David Cameron win the next general election. The council wants a basic service and charges for anything more sophisticated.

"People have got off their backsides and are getting involved in this issue," said David Young, 78, chairman of the UK Pensioners' Strategy Committee, which got the injunction so they can keep their wardens instead of the offered alternative of "floating" wardens to cover several sites from next year. Young said: "This affects 500,000 old people across the country."

The group's claim is that Barnet has acted unlawfully by ignoring the terms of the residents' tenancy agreements, its duties under the disability discrimination act, and the effect on tenants, particularly those who are disabled.